//写cookies
function setCookie(name,value,time)
{
	if(time==undefined){
	    var Days = 30;
	    var exp = new Date();
	    exp.setTime(exp.getTime() + Days*24*60*60*1000);
	    document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
	}else{
	    var strsec = getsec(time);
	    var exp = new Date();
	    exp.setTime(exp.getTime() + strsec*1);
	    document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
	}
}
//读取cookies
function getCookie(name)
{
    var arr,reg=new RegExp("(^| )"+name+"=([^;]*)(;|$)");
    if(arr=document.cookie.match(reg))
        return (arr[2]);
    else
        return null;
}
//删除cookies
function delCookie(name)
{
    var exp = new Date();
    exp.setTime(exp.getTime() - 1);
    var cval=getCookie(name);
    if(cval!=null)
        document.cookie= name + "="+cval+";expires="+exp.toGMTString();
}
function getsec(str)
{
   var str1=str.substring(1,str.length)*1;
   var str2=str.substring(0,1);
   if (str2=="s")
   {
        return str1*1000;
   }
   else if (str2=="h")
   {
       return str1*60*60*1000;
   }
   else if (str2=="d")
   {
       return str1*24*60*60*1000;
   }
}
